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United States Department of Agriculture

Agricultural Research Service

Title: Cryptosporidium Taxonomy: Recent Advances and Implications for Public Health

Authors
item Xiao, Lihua - CDC, ATLANTA, GA
item Fayer, Ronald
item Ryan, Una - MURDOCH U.,AUSTRALIA
item Upton, Steve - KANSAS UNIVERSITY

Submitted to: Clinical Microbiological Reviews
Publication Type: Review Article
Publication Acceptance Date: November 1, 2003
Publication Date: January 17, 2004
Citation: Xiao, L., Fayer, R., Ryan, U., Upton, S.J. 2004. Cryptosporidium taxonomy: recent advances and implications for public health. Clinical Microbiological Reviews. 17:72-97.

Interpretive Summary: Measurements of the oocyst stage represent the basis for taxonomy fof a large group of protozoan parasites including those in the genus Cryptosporidium. Measurements allow microscopists to identify large numbers of genera and morphologically distinct species, and the importance. These measurements have become one of the requirements for establishing a new species. However, in the case of Cryptosporidium, measurements alone ares not adequate and should not be the sole criterion for naming a new species. Oocysts of many species of Cryptosporidium are virtually identical in size, and similarities in oocyst structure have caused confusion about the validity of several Cryptosporidium species. Therefore, other characteristics must be included in the taxonomic description of Cryptosporidium species. In many cases, experimental animal transmission followed by light microscopy and sometimes electron microscopy of internal stages have proven useful. The present manuscript reviews all valid species of Cryptosporidium and literature pertinent to the taxonomy of the genus.

Technical Abstract: Currently, morphology, especially oocyst measurements, represents the cornerstone of apicomplexan taxonomy. Measurements allow microscopists to identify large numbers of genera and morphologically distinct species, and the importance of a good morphologic description cannot be understated. Therefore, oocyst morphology has become one of the requirements for establishing a new species. However, in the case of Cryptosporidium, morphology itself is not adequate and should not be the sole criterion for naming a new species. Oocysts of many species are virtually identical in size, and similarities in oocyst structure have even caused confusion about the historical validity of several Cryptosporidium spp. Because oocyst morphometrics alone are not entirely adequate for descriptions of new species of Cryptosporidium, other characteristics must be included in the taxonomic description. In many cases, experimental transmission followed by light and sometimes electron microscopy of endogenous stages has proven useful. The present manuscript reviews all valid species of Cryptosporidium and literature pertinent to the taxonomy of the genus.

Last Modified: 9/2/2014